Beam letoff



Amg.28,'1945.` PLUNKETT ETAL 2,383,562

BEAM LET-OFF Filed Dec. 29, 1942 a'sneets-sheet, v1

INVEN-roRs BRlAN PLUNKETT. ROBERT c, scH EIB.

Aug. 28, 1945. B. PLUNKETT ETAL 2,383,562

v BEAM LET-OFF Filed Dec. 29, .1942 2 Sheets-Sheet 2 ,ut #img numruunuuuuumrmmummmn i IV uruuuuwqgqguuuumumuuuuum INVENTORS BRIAN PLUNK ETT. ROBERT lC. SCHEIB A BY n MTITOEN: Egg I t Patented Aug. 28, 1945 BEAM LETOFF Brian Plunkett, Cumberland, and Robert C.

Scheib, La Vale, Md., asslgnors to Celanese Corporation of America, a corporation of Delaware Application December 29, 1942, serian No. 470,474

4 Claims.

This invention relates to warp-knitting machines and relates more particularly to a positive, continuous warp beam drive for letting oir yarns from the warp beams on which they are wound in a continuous manner.

In warp-knitting machines, the yarns from which the fabric is knitted are normally wound on one or more beams in the form of Warps. As the machine knits the fabric, the yarns are drawn slowly from the beams, causing the latter to rotate, and are knitted by the moving needles into the desired fabric. 'Ihe rotation of each beam is usually controlled by means of a brake which prevents the beam from rotating freely when the yarn is not being drawn oi and being released when tension is put on the yarn. 'I'he warp beam brake is usually released by the action of a tension rod operatively connected thereto, over which tension rod the yarns from the warp beam pass on their Way to the needles. When the knitting machine is started up a tension is placed on the yarns which causes the tension rod to be depressed. The downward movement of the tension rod as a result of the yarn tension releases the brake and permits the beam to rotate freely and to let off the yarns. 'I'his manner of letting oil the yarns whereby the yarn does some work is quite disadvantageous, however, since not only is an undue strain placed upon the yarns as well as upon .the needles, but an even more important factor is that the yarns are not fed freely to the moving needles as soon as the machine starts up. The tension rod must iirst be depressed before -the warp beam brake is released. When, for any reason, the machine is halted during the knitting operation, the tension rod rises and must be pulled down again by applying a tension on the yarns so that the beam brake is released and the warp yarns may again be drawn from the beam and fed tothe moving needles. Such a halt in the even feeding of the yarns causes an irregular stitch formation at the point where the operation was halted. This irregular course of stitches running across the fabric forms a mark, usually referred to as a stop-mark, which is clearly visible in the finished fabric. Such marks, of course, seriously detract from the appearance and the commercial value of the knitted fabrics.

When, for example, yarn is being drawn simultaneously from, say, two beams, as in the case where a two-bar fabric is being knitted, not only is the above tendency Atoward the formation of stop-marks present to a more pronounced degree, but yet another diillculty obtains. Thus,

where yarns from two separate beams are being knitted to form a single fabric, the fabric being knitted may be of such design that for a given number of stitches a greater amount of yarn is drawn from one beam than from the other. In such cases the amount of yarn Wound on each of the beams differs, and the yarns are drawn from each beam at different speeds during the knitting operation. No matter how carefully the yarn is measured as it is wound on each of the beams and run off from the same, it has been. found that with mechanisms now available the yarns cannot be run out with a suicient degree of accuracy to ensure having no yarn left on one beam when the yarn on the other beam has been exhausted. Excess yarn left on the beam in this Way constitutes one of the most prolic causes of knitting yarn waste. Usually, the yarns-which remain are of relatively short length and are unsuited for any other use. The elimination of these losses, i. e. losses due to excess yarn on the beam and to stop-marks in the finished fabric would, obviously, render knitting processes much more economical and satisfactory.

It is,` therefore, an important object of our invention to provide means for driving the beams in warp-knitting machines as well as other textile machines in a positive manner and to let off the warp yarns therefrom at a. controlled and even rate.

Another object of our invention is the pro'- vision of a plurality of Warp beams of such relative dimensions that said beams may be opera.- tively connected positively driven so that Warp yarns wound thereon will be let ,olf in a constant and unvarying linear ratio as said beams rotate.

A further object of our invention is the provision of a plurality of warp beams of such relative dimensions that said beams may be operatively connected and positively driven so that warp yarns wound thereon will be let off in a constant and unvarying linear ratio as ,said beams rotate.

Other objects of our invention, together with certain details of construction and combinationi of parts, will appear from the following detailed description and the accompanying drawings.

In the drawings, wherein the preferred embodiments of our invention are shown:I

Fig. 1 is a side elevational view of our novel Warp beam driving mechanism showing the yarns leaving a pair of Warp beams, which `beams are positively driven and operatively connected together as by suitable gearing,

Fig. 2 is a diagrammatic view in section of a plurality ofwarp beams containing yarn wound thereon, in which the dimensions of said beams have a. specific relationship one to the other. and

Fig., 3 is a front elevational view of another form of apparatus wherein yarns are let oil from a pair of warp beamsin a ilxed linear ratio. showing drive means for rotating the lower warp beam and a belt and pulley arrangement whereby the upper beam is driven from the lower beam.

Like reference. numerals indicate like parts throughout the several views of the drawings.

Referring now to thedrawings and more par ticularly to Fig. 1, there is shown a machine frame, generally indicated by reference numeral III, which frame carries a lower warp beam II and an upper warp beam I2 rotatably mounted thereon as by shafts I3 and I4, respectively. The

vlower warp beam II is rotated by means of a drive shaft I5 which rotates in bearings I5 and I1 which are suitably mounted, as shown. Drive shaft |5 causes the lower warp beam II to rotate through the action of a worm gear I3 keyed thereto, which worm gear meshes with a .gear I9 mounted on warp beamv shaft I3. The shaft I5 is, in turn, driven by means of a positive infinitely variable (P. I. V.) reducing mechanism 20. Power from the reducing mechanism 251s transmitted to shaft I5 through a worm drive gear 2| driven by gears 23 and 24 and meshing with a gear 25 keyed to shaft |5. The infinitely variable reducing mechanism 20 is driven by means of a drive chain 25 which runs at a constant speed and is in turn driven from some suitable power source (not shown) which is coordinated with and drives the knitting mechanism, as is well understood in the art. In order to drive the upper warp beam I2, shaft I3 on which the lower warp beam I I is mounted, is provided with a gear 21, which gear meshes with an idler gear 25. The latter drives a gear 29 which is fixed to upper warp bam shaft I4, the rotation of shaft I4 causing warp beam I2 to revolve. A l'I'he idler gear 28 rotates on a stub shaft 30 mounted on frame III. The gears are designed to operate at such ratios that the rotating warp beams have a relatively low angular velocity and the yarn is let off to the needles without undue slack. The rotation of upper warp beam I2 lets off a plurality of yarns indicated by reference numeral 3| and the rotation of lower warp beam I| lets off a plurality of yarns 32, each of the yarns being let oil' at a controlled and constant rate. 'I'he yarns are then directed to the knitting mechanism (not shown).

The rate at which the beam I Lrotates to maintain the yarn feed rate constant is controlled by the speed at which shaft I5 is driven. To maintain the yarn feed rate constant the rotational speed of the warp beam shaft must be gradually increased since, as the yarns leave the respective beams, the effective diameter of the warp beam continually decreases and for each revolution there will gradually be less yarn let off. This gradual increase in the speed of the warp beam is eifected by the action of a lever 33 having a roller 34 at one end thereof and attached at the other end to the speed control link 35 of the P. I. V. reducing mechanism 25 through a rod 35 attached to lever 33 by means of a U-shaped collar 31. Rod 35 is provided with a turnbuckle adjustment 38 by means of which the effective length of said rod. may be varied. Lever 33 is pivotally mounted on a pin 33, carrying a mit holes 43 at the end of the lever 33. As lever 33 slowly pivots at 39 dueto the gradual decrease in the effective diameter of beam Il caused by the run oif of the yarns, rod 35 shifts speed control link 35 causing it to effect an increase in the gear ratios in the P. I. V. reducing mechanism 2li, thus gradually speeding up the rotational velocity of drive shaft I5, and yarns 3| and 32 are thereby run oif and are fed to the needles at a constant and controlled rate.

In order to maintain yarns 3| and 32 at the desired tension throughout the stitch formation there is provided a yarn tension bar 44 xed in an arm 45 and a yarn tension bar 45 fixed in an arm 41. Arm 45 pivots on a shaft 45 set in frame I0 and arm 51 pivots on a like shaft 45. Shafts 48 and 43 go the full width of the machine. Pressure is maintained on arm 45 to resist tbe downward pull of yarn 3| by means of an adjustable spring 55 which is set on a threaded rod 5| and bears on the end 45 of arm 45. The degree of pressure exerted by the spring may be varied by adjusting a knurled nut 52. vIn like manner the tension arm 41 is maintained in'the desired position by means of a spring 53, set on a threaded shaft 54, which spring bears on the end 41' of arm 41 and is adjusted by knurled nut 55. It will be understood, of course, that tension rods 44 and 45 extend across the entire length ofv the respective warp beams and the opposite ends of said rods are supported and spring pressed in like manner. It will be observed that in accordance with our invention the warp beams are positively driven and no tension is placed on the yarns as the knitting operation is commenced. Instead, since each warp beam is driven the yarn is let oiI from the beams directly and does not have to be drawn oil', no undue tension is placed on the yarns, nor is it necessary for the yarn to do any work as it passes to the needles.

. When operating the device of our invention in the knitting of a two bar fabric requiring each of the warps to be fed to the needles at the same rate, the warps are wound so that they contain equal lengths of yarn and the top warp is so geared to the bottom Warp that each warp beam makes the same number of revolutions. The arrangement described above satisfactorily causes the two warps to run out at equal speeds.

When the top warp is required to feed in at a different rate than the bottom warp, however, merely gearing the warps together is quite insufficient where it is desired that the yanr feed from the respective beams be in a constant ratio. If the empty Warp beams are of the same diameter and, for example, one and one-half times as much yarn is wound on the top warp beam as on the bottom beam so that the yarns may run od together in a ratio of one and one-half to one, merely gearing the top warp beam solidly to the bottom warp beam in that ratio will not produce the desired result. A gear ratio which will hold good at the start of the knitting operation to let the respective yarns off in the desired linear ratio will not hold good at the end to maintain the let off in the same constant linear ratio since the diameter of each of the full warp beams is decreasing at a rate which is constantly changing. Thus, while a single revolution of each beam will let on the yarns in a speciilc linear ratio at the start, this ratio will not be constant all through .the knitting operation as the effective diameter of each beam decreases. If, however, the upper warp beam is replaced by another beam wherein the diameter of the new upper warp beam is such that it bears a definite relationship to the amount of yarn to be wound thereon and to the diameter of the lower warp beam, the respective filled warp a--the radius of the original warp beams or cores,

empty B=the outside radius of the lower warp beam,

nlled r=new upper warp beam radius or core, empty R=new upper warp beam radius, filled beam shaft I3, a frusta-,conical pulley 59 keyed to upper warp beam shaft I4, and an endless belt S0 adapted to pass around said pulleys. Since beams Il and I2 are of unequal initial diameter and the effective beam diameters thereof change constantly as the yarns run olf, it is necessary, in order to maintain'the yarn let olf from beam l2 in a precise linear ratio to the constant let oi from beam H, to change the ratio between conical pulleys 58 and 59. This change is effected by shifting the position of belt 60. This change in ratio between conical pulleys 58 and 59 is controlled by the changing position of a control roller 6| which is adapted to be nconstant contact with the surface of the yarn on upper warp beam I2.

' Roller 6I is rotatably mounted on an arm 62 b=the outside radius of the top warp, llled, be-

fore being replaced by the new upper warp beam with filled radius R,

if r and R are in such relationship to the foregoing dimensions that Rnd `the respective warp beams of dimensions a, B,'

r and R may be solidly geared together and when so geared will let on the yarns therefrom in a constant and unvarying linear ratio. Accordingly, since the dimensions a, b and B as defined are known, i. e. these dimensions are those which were normally employed heretofore, the substitution of these values in the formulae given above will yield, by solving one formula., the desired dimension for the radius of the new upper warp beam when empty, i. e. radius r, and by solving the other formula, the radius R, i. e. the radius of the filled warp beam, may be obtained. Ernploying an upper warp beam of radius r wound with yarn so that it has a. radius R, a gear arrangement of the required gear ratio connecting lower driven warp beam il having the dimensions a and B with the said upper warp beam, will permit the run od of the yarns 3l and 33 from said warp beams in a constant and unvarying linear ratio from the beginning to the end of the knitting operation.

In Fig. 3 there is shown an embodiment of our invention lwherein other means are employed for maintaining the yarn feed fromtthe warp beams to the knitting mechanism in a constant linear ratio. In this embodiment, as in the embodiment shown in Fig. 1 lower warp beam l i is mounted on shaft I3 and upper warp beam i2 is mounted on shaft i4, the shafts t3 and id being journaled in suitable bearings 56 and 5l', respectively, on frame iii. The lower warp beam Il is driven and its speed controlled in the same manner in both modifications. However, in the modification shown in Fig. 3, the upper warp beam l 2 is driven--and its speed controlled by different means.

Thus, the rotation of warp beam H is transmitted to warp beam l2 through means comprising a frusta-conical pulley 58, keyed to lower warp which is attached througha link 63 to a collar t4 keyed to a shaft t5. As the effective diameter of warp beam i2 decreases due to the yarn being run on?, roller ti moving toward the beam causes shaft 65 to rotate slowly. This slight but continuous rotation of shaft 65 is stepped up by a suitable gear train in gear box 66 which transmits the enhanced rotation to a threaded shaft bl. Mounted on shaft Sl is a threaded carriage S8 which slides on a guide bar 89 and carries a fork it so positioned as to engage the edges of belt Si). The pulleys, as well as the other mechanism, are enclosed by a guard ii which is attached to frame id. The rotation of threaded shaft Si causes carriage 68 to move gradually in a. horizontal direction and this movement carries belt t@ with it, causing the latter to move across the driving surface of pulleys d and 5d. Since the pulleys are of conical shape, every position of the belt represents a slightly different ratio between the rotational speed of the lower warp beam il and the upper warp beam i2. The pulleys are so designed that they cause ,the upper and lower warp beams to rotate at speeds such that the respective yarns are let off from each of the warp beams at a uniform even rate which, due to the pulley dimensions, remains in a predetermined, linear ratio throughout the entire simultaneous run on of the yarns from each beam.

Not only d'oes the device of our invention enable warp knit fabrics to be knitted without the formation of stop-marks and with the elimination of yarn waste, but there is yet another advantage which is observed when said device is employed. Owing to the fact that in each instance .the yarn is positively fed to the needles and the yarn guides and needles do not have to pull the yarn from the warps, the knitting elements -of the machine maintain correct alignment much longer and wear on such parts is greatly reduced. Furthermore, since better alignment can be maintained', greatly increased machine speeds are possible.

It is to Ibe understood that the foregoing detailed description is given merely fby way of illustration and that many variations may be made therein without departing from the spirit of our invention.

ling the speed of said rotating packages, said speed controlling means being responsive to the quantity of yarn on at least one of said packages, whereby the yarns are simultaneouslyvand continuously let oii' said packages in a positive manner and are fed to a textile mechanism at a constant and unvarying ratio.

2. In textile apparatus for letting of! yarns.

simultaneously from a pair of interconnected packages thereof, the combination with a drive shaft geared at one end and adapted to rotate continuously one of said packages and driven at the other by a positive infinitely variable gear drive mechanism, of a. gear train cooperating with said rotated package and adapted to rotate continuously the other of said packages, and means for controlling the speed of said rotating packages, said speed controlling means being responsive to the quantity of yarn on at least one of said packages, whereby the yarns are simultaneously and continuously let oi said packages in a positive manner and are fed to a textile mechanism at a constant and unvarying ratio.

3. In textile apparatus for letting of! yarns simultaneously from a pair of interconnected packages thereof, the combination with 'a drive shaft geared at one end and adapted to rotate continuously one of said packages and driven at the other by a positive infinitely variable gear drive mechanism, of a gear train cooperating with said rotated package and adapted to rotate continuously the other of said packages, and

position of said means for controlling the speed of said rotating packages, comprising a pivotally mounted lever carrying a roller at one end thereof in contact with the yarn surface on said iirst-mentioned package, and fixed at the other end to the speed control link of the package driving means, the roller and lever responding to the quantity of yarn on said package, whereby the yarns are simultaneouslyvand continuously let on said packages in a positive manner and are fedto a textile mechanism at a constant and unvarying ratio.

4. In a textile operation, the step of positively and simultaneously unwinding yarn from two operatively connected, rotating yarn packages at a xed and unvarying linear ratio, one package having a. core radius of a and a full radius of B and the other package having a core radius of r and a full radius of R, r being equal to and R being equal to yarn yielding radius Ron a core of radius r on to a core of radius a.

BRIAN PLUNKE'IT. ROBERT C. SCHEIB. 

